This invention relates to a system and method for treating water acquired from a freshwater source to generate potable water.
Drinking water is one of the fundamental requirements of any civilization, much effort has gone into the development of devices and methods for generating and refining drinking water. As civilization has progressed, the quality and availability of safe drinking water has improved dramatically. While it is often no longer necessary for individuals to arrange for their own procurement and treatment of water to make it safe for drinking, insofar as those functions are available through a municipality or other government entity or a private entity, there does remain a need to provide systems and methods for the treatment of water to remove impurities. This need is especially pronounced in underdeveloped regions and countries and in times of drought. For those regions or countries wherein the government cannot afford or chooses not to provide, regulate and maintain a system to treat water to provide drinking water, it is desirable to provide a system and method whereby water from freshwater sources, such as lakes, streams, ponds, rivers, etc., can be accessed and treated to provide safe drinking water.
Even for areas in which a governmental or private entity is treating water to remove impurities and to make the water safe for human consumption, it is desirable to provide a system and method to remove impurities, which often include chemicals added by the government or private entity treating the water. Specifically, while tap water has been treated by the government or private entity to make it safe, typically through the addition and blending of chemicals into the water, often those chemicals, while not being unsafe or posing any health risk, give the water a bad taste or odor and may cause residual impurities to form. The dramatic increase in sales of bottled water, and in fact the growth of a whole industry providing pure water without impurities and with improved taste, demonstrates the undesirability of treated tap water as drinking water. Thus, to further refine the water available from a government or private entity engaged in the treatment and purification of water, it is desirable to provide a point of entry system and method to remove impurities that remain after treatment by a governmental or private entity.
As the population of the United States continues its migration away from urban centers toward more rural settings, it becomes more costly for the government to extend its services, including the provision of water. Real estate development continues to occur in areas in which water is not available from a government or private entity, and in those cases homeowners must have provisions for accumulating water, such as in a cistern or from a well, and treating the water to remove impurities. It is thus desirable to provide a point of entry water treatment system and method to treat and remove impurities from water retained in a cistern, well, or other storage device.
Many of the prior solutions directed to the generation of potable water have been concerned with the treatment of saltwater to remove salt therefrom to make it into drinking water. The chemical treatment is dramatically more complex than that required for the treatment of freshwater. The present invention is directed solely to the treatment of freshwater and does not concern itself with saltwater.
Recreational activities have also created a need for a system and method for treating freshwater to remove impurities and to provide potable water that is free of any of the negative effects of the treatment, including the odor and taste of chemicals used in the treatment. Applications of such a point of entry water treatment system and method include use while boating on a lake, river or other freshwater body of water. Another application is use by campers or military units in the field in which a point of entry water treatment system is desirable that turns a freshwater source in a remote environment into potable water free of the negative odors and tastes of the chemicals and devices used in the treatment of the water.
Because of the multiple applications available for a point of entry water treatment system that treats freshwater to provide potable water, it is desirable that such a system be provided that is adaptable to a variety of circumstances. It would be advantageous, for example, to provide a single system and method for treating freshwater to generate potable water that can be applied to a house to provide drinking water for the residents thereof, while also being capable of being applied to a boat or field campsite in close proximity to a freshwater source.
Previous attempts to provide a system for treating water to provide potable water have typically included the use of reverse osmosis involving passing water through a semi-permeable membrane, particularly in those systems that include application of a disinfectant, such as chlorine, in the treatment of the water. The use of reverse osmosis is disadvantageous, however, because the rate at which water is processed thereby, i.e. passes through the membrane, is very slow and is directly proportional to the cross-sectional area of the membrane through which the water is being treated. To generate the throughput necessary to provide a supply of drinking water to a family, a membrane having a very large cross-sectional area is required. It is thus desirable to provide a point of entry water treatment system and method that continuously treats fresh water, including provisions for mixing a disinfectant with the water and allowing sufficient residence time for the disinfectant to work, without limiting the throughput of the system.
Because the use of chemicals, particularly disinfectants such as chlorine, may be damaging if injested in too great a concentration, it is also desirable to provide means for controlling the disinfectant added to untreated water to ensure that system output cannot erroneously output water with too great a concentration of disinfectant.
There is thus identified a need for a point of entry water treatment system and method that provides adequate potable water throughput at acceptable pressure and which is sufficiently flexible and adaptable for use in homes having city water; in homes that do not have city water; on freshwater boats; and at camp sites, military or other field installations.
It is an object of the present invention to provide a point of entry water treatment system that outputs an acceptable volume of water that has been treated to remove impurities while being relatively portable and adaptable to a variety of uses.
It is another object of the present invention to provide a point of entry water treatment system that is modular and performs three steps of treatment to water including pre-filtering to reduce turbidity, chemically disinfecting using diluted sodium Hypo-chlorite, and post-filtering to remove free chlorine, chlorine by-products resulting from the disinfecting, and other impurities not affected by the disinfecting process such as pesticides and volatile organic chemicals.
It is yet another object of the present invention to provide a point of entry water treatment system having interlocking controls to prevent raw disinfectant or untreated water from exiting the system.
It is a further object of the present invention to provide a point of entry water treatment system adaptable to provide potable water on a boat; in a home to treat cistern water, well water or city water; or at a camp-site or military installation to treat freshwater in the field.
It is a further object of the present invention to provide a system to generate potable water from a freshwater source utilizing two filters and chemical disinfection.
It is yet another object to provide a method for the treatment of fresh water to produce potable water free of impurities and free of disinfectants used in the treatment thereof.
These and other objects and advantages of the present invention will be apparent from a review of the following specification and accompanying drawings.
The present invention comprises a point of entry treatment system for fresh water that provides a pre-filter means for reducing turbidity in the water, means for applying a disinfectant to the water, and post-filter means for removing disinfectant and disinfectant by-products resulting from applying the disinfectant to the water. The means for applying a disinfectant is continuous and further comprises an in-line mixer and a mixing tank. By making the process continuous and not relying upon the passage of water being treated to pass through a membrane, as in a reverse osmosis system, the speed of processing water is greatly enhanced.
The means for applying a disinfectant further comprises a main pump transferring untreated fresh water from a source to the pre-filter means and a metering pump injecting a disinfectant into the flow stream ahead of the in-line mixer, the disinfectant being thoroughly mixed in the in-line mixer along with water exiting the pre-filter means to ensure complete contact with the disinfectant. The control means of the system are designed to allow only treated water to exit the system and comprises interlocking co-dependent permissive circuits between the main pump and the metering pump. By having the circuits interlocking and co-dependent, it is impossible to have one running without the other, so there is no danger of outputting untreated water.
The disinfectant of the most preferred embodiment of the present invention is sodium Hypo-chlorite and the post-filter means comprises an activated carbon filter.
In a significant feature of the present invention, the system for treating fresh water comprises a modular system wherein all components are mounted to and within a frame. This gives the present system the capacity to be easily moved from site to site, an extremely pertinent feature for campers and military, and it also can readily be applied to a boat to generate clean water free from impurities from murky lake or river water.
In another significant departure of the present invention from the prior art a pressure tank is provided for in line storage of water that has been disinfected and allows periodic cycling of said main pump so that on and off transitions occur less often. The pressure tank is particularly advantageous because it dampens out the repetitive on and off cycling of the main pump, thereby extending the life of the pump and, indeed, of the whole system.
A method for treating water to generate potable water is also disclosed herein, the method including the steps of applying water acquisition means to bring in water, followed by passing the water through a sediment filter to reduce turbidity. Next, the water is mixed with a disinfecting chemical to neutralize impurities remaining in the water after which the water is transferred to the mixing tank in which it will remain for at least 20 minutes. Finally, the water is passed through an activated carbon filter, preferably a Granular Activated Carbon (G.A.C.), filter to remove free chlorine remaining in the water and to separate out the chlorine by-products.
The present invention is advantageous over the prior art in several ways. First, it provides a relatively portable water treatment system that removes not only the sediment, but also chemically treats the water and then significantly reduces the chemical, chlorine, and all of its byproducts remaining after passing through the G.A.C. filter. Second, the control of the system ensures that only treated water will exit the system by interlocking the controls between the main pump and metering pump.
The third distinguishing characteristic of the present invention is that, by including a pressure tank in the system, excessive cycling of the main pump is eliminated because the pressure tank and a related pressure switch operate the system within a range of pressures, so that the main pump will run to fill the pressure tank and pressurize the system. Water is then used out of the system to deplete the contents of the pressure tank first, thereby reducing pressure in the system, and, when the system pressure falls below a minimum set point, the main pump and metering pump will turn on to re-fill the pressure tank. Once the pressure tank is re-filled and the system re-pressurized, the pumps are turned off and await the next cycle.